As a clean and renewable energy source, wind energy has been widely recognized in various countries around the world. Wind generation is a procedure of conversion of the kinetic energy of wind into electricity. The use of wind power is environmentally friendly, and the amount of electricity that can be generated is enormous. With the development trend of large-scale and offshore wind power, megawatt-class high-power wind turbine generator will become dominant in the international market.
When blades of the wind turbine rotate and swing, the hub thereof will transmit a large force to various transmission components of the wind turbine generator, causing vibration of these components and generating noise. Therefore, the design of the vibration-damping system for each component is particularly important. In order to ensure stable operations of various components in the drive system of the wind turbine generator, and to reduce the vibration and noise generated by the system's operation as much as possible, it is necessary to adopt corresponding measures for vibration and noise reduction. Among others, the vibration reduction of the gearbox is particularly important, for which a proper vibration-damping support must be provided. In order to dampen the torsion moment transmitted from the main shaft to the gearbox, the vibration-damping support structure of the gearbox should provide a large load-bearing capacity when a large load is reversed.
CN103075461B discloses a vibration-damping support device for a gearbox of a wind turbine generator, the device being mounted on both sides of the gearbox of the wind turbine generator. An upper end of the vibration-damping support device is connected to an extension arm of the gear box of the wind turbine generator, and a lower end thereof is connected to a main frame. Similar to other vibration-damping support devices in the prior arts, the stiffness value of this vibration-damping support device is approximately a constant value, which is generally kept unchanged. However, in the case where the stiffness of an elastic support device is constant, when it is subjected to a large load, it can be concluded, based on related formula, that the deformation of the elastic support device will be particularly large. This large deformation will result in large oscillations of the components to be dampened, so that rigid collisions may occur at some locations. At the same time, the rubber parts are also easily damaged. Therefore, in the field, it is desirable that the stiffness value of the vibration-damping support device can be varied, so as to provide, for example, better vibration damping effect, and also protect the components to be dampened and the vibration-damping support device.
CN103363005A discloses a tapered vibration damper with adjustable rigidity, which includes a base, a stiffness adjusting device, an elastic member, and a height adjusting device. Among others, the stiffness adjusting device includes a slider, an adjusting bolt, a top block, and a spring. In this tapered vibration damper, the adjustment of stiffness is achieved essentially through an additional stiffness adjustment device. However, this stiffness adjusting device is complicated in structure, occupies a certain amount of installation space, and also increases the costs.